You Can Buy For Under 6 $
http://www.deal-shop.com/product/baby-einstein-take-along-tunes-musical-toy/

My 6 month old son loved this toy ever since he was 2 months old. When he's fussy in the car I just give this toy to him and he calms down immediately! There are two volumes so if we are in the car I turn it to the highest volume and if we're in a public place or my office I just turn it down. The songs are long enough that they grab his attention for a few seconds. He loves to look at the blinking lights that play along with song as well. I feel this will be a toy he will enjoy for a while.
The baby's grandmother got her this toy as a Valentine's Day gift (the baby was around 14 weeks old), and she was immediately mesmerized. she loved having a "screen" of her own to look at, loved the music and the bright lights. As an adult I like it because it plays classical music and displays the notes; for the mom of a baby who has an affinity for music already, it is great. The tones of the music are also not jarring, tinny, or cheap-sounding. It's not a piano or a symphony, but the tones are almost soothing.

But here is the #1 reason why this product got 5 stars from me (and from the baby): before this toy, my baby hated tummy time. She would cry through it and we couldn't bear to go through with it. She is still too young to press the buttons regularly although she is starting to understand the cause and effect when mommy takes baby's finger and presses the big, easily pressed button for her, and she can hit it a few times, but for tummy time we turn it on for her. She loves looking at the screen to distract her from exercise--almost like watching TV while running the treadmill! The music and the lights motivate her, and thanks to this toy our baby was able to exercise enough to roll on her back on the first try! I just wish Baby Einstein made more of these with different tunes so we could play more of them while she does Tummy Time. No other toy has distracted her or kept her entertained during tummy time like this one!
https://www.youtube.com/watch?v=WUaSHZ4EtaI